Magnetic controlled rotary speed responsive switch



June 19, 1956 .1. K. GAYLORD EI'AL MAGNETIC CONTROLLED ROTARY SPEED RESPONSIVE SWITCH Filed Jan. 29, 1954 W% QwmmaQym/m/ 8 M M10 "m J 5 ml wa 7 W 4 3 Va w A 50 I Ufliad sates O This invention relates to improvement in a speed responsive switch and refers particularly to an electric switch which functions to open an electric circuit in response to the rotational speed of a body. v

In a rotary speed response switch such as shown and described in patent applicationof Lewis E. Thatcher, Serial No. 308,085, filed September 25, 1952, now Patent No. 2 ,678,977,issued May 18, 1954, wherein a hingedly mounted vane rotates in a pool of liquid and is; acted upon by the liquid to cant or rock the vane (which comprises oneterminal of the switch) away from the other terminal of the switch when a predetermined speed of rotation of the vane occurs, the speed; at which the switch responds is determined by the surface area of the vane, exposed to contact with theliquid, the effective weight of the vane and the q uantity and viscosity of the liquid through which the vane moves,

The present invention contemplates a switch of the" type described in said pending application wherein mag netic means is contemplated for rendering the vane more stable and less responsive to relativelylow rotational speeds, whereby the switch will not act until a predetermined higher speed'is reached than the speeds to which the device of thepending applicationfunctions; V p

The device of the present application contemplates the' use of magnetic attraction as a resistance to movement of the vane from its normal position, that is, the

position at which the switchi s closed, whereby a'r ela tively high rotary speed must'be imparted to the: vane before the liquid resistanceto the movement thereof overcomes the attractive resistance of the magnet employed. The features, objects and advantages of the present invention will be more apparent from the accompanying drawing and following detailed description.

In thedrawing, V n Fig. 1 is a longitudinal sectional view of an embodiment of the pr'esent invention. v Fig. 2'is a transverse sectional view ofthedevic'e shown in Fig. 1, taken on line 2 2 fFig. 1.

Fig; 3 is a detailed perspective view' of the vane em ploy'e'd, parts being broken away to show the carried magnet.

Fig. 4 is a view similar to Fig. 1' of a modification of the invention. I n I v p p p I V Fig. 5 is a view off'the vane employed in the'inodi fied device, parts being broken away to sh w the ferroma netic block adapted to be' acted en'by the magnet employed.

Although the present invention may be employed in silbstantially any environment and conjunction with ny type of rotating body tocontrol a desired ele'ctrical'cii can, for pnrpbsesof illustration, the d vice will b' d scribed in c'onjunction withits use on an' automotive" vehicle wherein the rotating'body comprises the usual speedometer cable. I n v M Refrfrifig, w h ng. a d n pa u r t F a t .1; 2 and 3 1 indicates generally the speed-responsive switch nab-saying" the concepts of the I resent invention; The device 1 comprises a cup-shaped body 2 having a top 2,751,454 Patented June 19, 1956 ice closure 3. The cup-shape d body 2 has abottom 4 and cylindrical side wall S. Within the body 1, a central cylindrical boss 6 is positioned whereby an annular space- 7 is provided in the body.

The body also carries a downwardlyextending cylin drical sleeve 8 which is provided with an opening 9 for the reception of an end of a speedometer sheath- 10' within which a speedometer cable 11 is' carried. The cable 11 extendsupwardly through the boss 6 andalso' through a sleeve 12 comprising a'portion of closure 3.;

The sleeve 12 is provided with an opening 13' adapted for the engagement of a spaced end14'of the speedometer cable sheath.

Within the boss 6:, a frictional gripping member 1'5 engages the speedometer cable 11, said member being em-j braced by a sleeve 16 which'is rotatably positioned within boss 6. A cap17 is rigidly positioned upon the sleeve 16 and member 15 is journaled within the closure 3 for rotation with the speedometer cable.

A shaft 18 is secured to cap 17 and extends radially outwardly from said cap into the upper portion of the annular space 7. A vane 19, which may comprise a metal" member, is folded upon itself to provide a sleeve 20 at its upper portion, said sleeve being adapted to loosely embrace shaft 18. Shaft 18 is of materially smaller diameter than the inner portion of sleeve 20 and, hence,

the sleeve is permitted a degree of radial movement upon: said shaft. A lug 21 is carried upon the end of shaft 18 and functions to prevent unintended movement of vane 19 axially of said shaft. i

The vane 19 has two spaced parallel sides 22, said sides being spaced by a permanent magnet 23 which is generally of the horseshoe type having two'dow'nwardly extending poles 24, the lower edgesof which are flush with the lower edges of they sides 22.

A pair of'rings25 and 26 constructed of ferromagnetic metal are concentricallydisposed upon the bottom 4, ring 25 being the outer ring and ring 26 being the inner ring. A copper ring 27 is disposed between the rings,

extends above the upper surfaces of said ferromagnetic rings. The vane: 19 carried by shaft 18 is disposed above the rings 25', 26 and 27, and under normal conditions, that is, when vane 19 extends vertically from shaft.i18,- the central portion of the lower edges of the sides 22 of the vane contact the copper ring 27. Thus, the poles 24 of the magnet 23 are disposed immediately above the rings 25 and 26.

In the operation of the device, a pool of non-conducting fluid 28 is positioned in the annular space, 7. Hence; when the speedometer cable 11 is rotated, the vane 19 is carried circularly within the zone 7. The movementof vane 19 through the fluid 28 results in a force being applied to the wine by the frictional resistance of the fluid upon said vane; This force tends to rock or cant the'vane about the shaft 18; When a: predetermined'speed' ofrotation' of the vane is reached the vane will'be so canted" that' the lower edges thereof will break Contact with the copper ring 27. Thus, an electricalcircuit"(not shown) connected between ground 29 and conductor 30; which latter isconnected to the ring 27, will be broken.

The poles of magnet 23 are normally disposed adjacent to the rings '25 and "26 and, hence, a force of attraction exists between the magnet and said ferromagnetic'ringst This attractive'force tends to" inhibit further separation of the magnet from the rings 25 and 2s and, hence, until a'speed ofrotation is reached which will'enable th'e fluid resistanceacting upon the vane to overcome thisattra'citiveforce, the circuit comprising ground 29 and conductor ever, the circuit will be broken.

It can readily be seen that the switch 1 may be caused to respond to different speeds of rotation merely by employing magnets of increased or decreased strength. In addition, because of the attractive pull of the magnet 23 the normal pressure of the edge of the vane upon the copper ring is augmented and, hence, good electrical contact will be obtained between these parts.

Referring particularly to Figs. 4 and 5, 31 indicates a modified form of rotary speed responsive switch. The Switch 31 is substantially identical to switch 1 except as to the relationship of the vane to the rings employed. Hence, to eliminate the necessity of describing obvious identical parts in the two forms of the invention, similar reference numerals, without further description, will be applied to identical parts.

In the form of the invention shown in Figs. 4 and 5, the vane 19 carries between its opposed sides 22 a bar .32 of ferromagnetic material in place of magnet 23 shown in Fig. 3. The bar 32 preferably has its lower edge flush with the lower edges of the sides 22.

Three rings 33, 34 and 35 are concentric and comprise permanent ring magnets and ring 34, also concentric, is preferably constructed of copper or other good conductor. Ring 34 is thicker than the ring magnets 33 and 35 and its upper face extends above the upper faces of the magnets.

In operation, bar 32 carried by the vane 19 is subjected to the attraction of ring magnets 33 and 35 and, in the fashion described in conjunction with switch 1, the vane 19 carrying bar 32 will not be canted out of contact with copper ring 34 until the resistance of the fluid 28 upon the vane exceeds the attractive force of the ring magnets upon the bar 32. By changing the strength of the ring magnets 33 and 35 or by decreasing the gap between the bar 32 and the rings 33 and 35, the switch can be made to respond at a higher critical rotating speed of cable 11. Vice versa, by weakening the magnets 33 and 35 or by increasing the space between bar 32 and the rings 33 and 35, the switch may be made to respond at a lower rotating speed of cable 11.

Thus, in both forms of the invention shown and described, a switch mechanism is contemplated wherein by slight changes in the relationship between the magnets and the ferromagnetic armature or keeper the response properties can be changed.

We claim as our invention:

1. An electric switch responsive to the rotary speed of a body which comprises a container, an electrically conductive member carried in the container, said contianer being adapted to carry a non-conductive liquid above said conductive member, an electrically conductive element, means for pivotally suspending said element above said electrically conductive member with a free end portion thereof dipping in said non-conductive liquid and in contact with said electrically conductive member when said element is stationary, means for rotating said element in a plane substantially parallel to said electrically conductive member to cause the free end portion of said element to be deflected by friction between said nonconductive liquid and said element to cant said free end portion away from and out of contact with said conductive member, magnetic attractive means adjacent the free end portion of said element for urging the free end portion of said element toward said conductive member for opposing the canting of said element, and means for connecting the conductive member and conductive element in an electirc circuit.

2. An electric switch responsive to the rotary speed of a body which comprises a container, an electrically conductive member carried in the container, said container being adapted to carry a non-conductive liquid above said conductive member, an electrically conductive element, means for pivotally suspending said element above said electrically conductive member with a free end portion thereof dipping in said non-conductive liquid and in contact with said electrically conductive member when said element is stationary, means for rotating said element in a plane substantially parallel to said electrically conductive member to cause the free end portion of said element to be deflected by friction between said non-conductive liquid and said element to cant said free end portion away from and out of contact with said conductive member, annular ferromagnetic means carried adjacent said conductive member in said container, separate ferromagnetic means carried by said conductive element, one of said ferromagnetic means comprising a permanent magnet whereby a magnetic attractive force is exerted between both ferromagnetic means for opposing the canting of said element, and means for connecting the conductive member and conductive element in an electrical circuit.

3. An electric switch responsive to the rotary speed of a body which comprises, a container, annular metallic electrically conductive means carried in the container, said container being adapted to carry a non-conductive fluid above said metallic conductive means, a vane constructed of metallic electrically conductive material, means for pivotally suspending said vane above said metallic conductive means with a free end portion thereof dipping in said fluid and in electrical contact with said electrically conductive means when said vane is stationary, means for rotating said vane in a plane substantially parallel to said metallic conductive means to cause the free end portion of said vane to be deflected by friction between said fluid and said vane to cant said free end portion away from and out of contact with said metallic conductive means, said annular metallic conductive means comprising a ferromagnetic material and a portion of the free end portion of said vane comprising a ferromagnetic material, one of said ferromagnetic materials being a permanent magnet whereby a magnetic attractive force is exerted between both ferromagnetic materials to oppose the canting of said vane, and means for connecting said metallic electrically conductive means and said vane in an electrical circuit.

4. An electric switch responsive to the rotary speed of a body which comprises, a container, a plurality of metallic rings carried in the container, said container being adapted to carry a non-conductive fluid above said rings, a vane constructed of metallic electrically conductive material, means for pivotally suspending said vane above said rings with a free end portion thereof dipping in said fluid and in electrical contact with at least one of said rings when said vane is stationary, means for rotating said vane in a plane substantially parallel to said rings to cause the free end portion of said vane to be deflected by friction between said fluid and said vane to cant said free end portion away from and out of contact with said contacting ring, at least one of said rings comprising a ferromagnetic material and a portion of the free end portion of said vane comprising a ferromagnetic material, one of said ferromagnetic materials being a permanent magnet whereby amagnetic attractive force is exerted between both ferromagnetic materials to oppose the canting of said vane, and means for connecting said rings and said vane in an electrical circuit.

5. An electric switch responsive to the rotary speed of a body which comprises, a container, a plurality of concentric means carried in the container, said container being adapted to carry a non-conductive fluid above said rings, a vane constructed of metallic electrically conductive material, a ferromagnetic member carried by said vane, means for pivotally suspending said. vane above said rings with a free end portion thereof dipping in said fluid and in electrical contact with one of said rings when said vane is stationary, said ferromagnetic member being positioned adjacent the free end portion of said vane, means for rotating said vane in a plane substantially parallel to said rings to cause the free end portion of said vane to be deflected by friction between said fluid and said vane to cant said free end portion away from and out of contact with said contacted ring, at least one of said rings comprising a ferromagnetic material, said ferromagnetic member being a permanent magnet whereby a magnetic attractive force is exerted between said member and said ferromagnetic ring to attract the free end portion of said vane to said ring and to oppose the canting of said vane, and means for connecting said contacted ring and said vane in an electrical circuit.

6. An electric switch responsive to the rotary speed of a body which comprises, a container, metallic electrically conductive means carried in the container, said container being adapted to carry a non-conductive fluid above said metallic conductive means, a vane constructed of metallic electrically conductive material, means for pivotally suspending said vane above said metallic conductive means with a free end portion thereof dipping in said fluid and in electrical contact with said electrically conductive means when said vane is stationary, means for rotating said element in a plane substantially parallel to said metallic conductive means to cause the free end portion of said vane to be deflected by friction between said fluid and said vane to cant said free end portion away from and out of contact with said metallic conductive means, said metallic conductive means including a permanent magnet and a portion of said vane adjacent the free end portion thereof including a ferromagnetic material whereby a magnetic attractive force is exerted between said permanent magnet and said ferromagnetic material to attract said free end portion of the vane to the magnet and to oppose the canting of said vane, and means for connecting said metallic electrically conductive means and said vane in an electrical circuit.

Brandt May 11, 1943 Heintz Mar. 21, 1944 

